1. Technical Field
The invention relates to a pitch pocket construction and method of forming the same for sealing the junction between an element projecting through an opening in a waterproof membrane covering a roof substrate to provide a waterproof seal therebetween. More particularly, the invention relates to such a pitch pocket and method which reduces penetration of the waterproof membrane by eliminating anchors or screws which normally hold the pocket in position and which reduces labor and material costs by simplifying the application and construction of the pitch pocket.
2. Background Information
It is common practice in the roof construction art to form a waterproof seal between the waterproof membrane which covers the roof substrate and various projecting members such as vent pipes, support straps, conduits, guide anchors and similar elements which extend upwardly from the roof and pierce the covering membrane. One type of structure commonly used is referred to as a pitch pocket or pan which surrounds the projecting element and which has a sealer which is poured into to pan to seal around the projecting element. Typically, the pitch pocket is made of metal or plastic and must be anchored through the waterproofing membrane into the supporting roof substrate, which due to these attachment anchors present other possible areas or openings in the membrane which are subject to leakage.
Therefore, it is desirable, in forming such pitch pockets, to reduce or eliminate penetration of the waterproofing membrane when installing the pitch pocket by eliminating any anchors or screws which normally hold the pocket in position, and to reduce the time and materials required for installing and forming the pitch pocket to reduce the cost of the roof installation.
Various types of pitch pocket, pans and associated devices have been proposed for achieving these results, examples of which are shown in the following patents.
U.S. Pat. No. 3,838,544, discloses a pitch pocket formed of a plurality of plastic corner units which are assembled into a rectangular configuration about conduits and projecting members and is secured to the roof by sheets of tar paper.
U.S. Pat. No. 3,945,163, discloses a plastic box having an integral lower flange which is covered by roofing material for securing it to the roof. A plurality of cup-shaped sections are formed in a top cover of the box for selective removal to receive projecting pipes of various diameters. A rubber boot is then held in place against the pipes by strap clamps to form a waterproof seal.
U.S. Pat. No. 4,635,409, discloses another pitch pocket having a rectangular shape formed by a plurality of plastic J-shaped sections which are interfitted with each other and secured to the roof by the same material as that used to cover the roof and an adhesive. The individual J-shaped members are secured together by fastening screws to form the desired size of pocket for receiving a filler material.
U.S. Pat. No. 4,730,421, discloses another pitch pocket for forming a seal around a projecting pipe wherein the box is formed of molded plastic. The box is placed around the pipe to be sealed and includes a base portion. A flashing is applied to the upper surface of the base and extends to the upper surface of the roof structure. The sheet material is an elastomeric and is cemented in place. When the box has been positioned, it is then filled with a filler material in the lower portion thereof surrounding the pipe, and then a roofing tar is used to complete the fill.
Another known sealer pocket construction consists of a strip of metal attached to a strip of an elastomer having a pressure sensitive adhesive applied thereto which is covered by a protective release paper. To form and install the sealer pocket, the release paper is removed and the metal band formed into a ring and placed about the projecting member. The elastomer sheeting forms a flange about the outside of the ring with the top portion of the rubber extending along the side of the formed metal ring. A pourable sealer then fills the area within the metal ring.
Although many of these prior pitch pockets and sealing constructions and methods may provide satisfactory results, they use metal which can rust and is difficult to form satisfactory, and most importantly, are considerably more expensive than certain plastic components and require the use of a relatively expensive strip of flashing and associated adhesive. Furthermore, these metal components can be sharp and cut or pierce the rubber membrane. Likewise, it may be difficult to achieve a good seal with the metal due to the non-compatibility of the adhesive or sealant between the metal and rubber components. Also, these prior methods require additional assembly steps, all of which increase the overall cost of the installation on a roof.
Therefore, the need exists for a pitch pocket and installation method which simplifies field application and which reduces the cost of materials, and which uses materials which have no limiting shelf life and will not rust or result in excess cracking over a length of time after being installed on a roof.